CAC Calculator — Cost to Acquire a Customer & Payback

How to use

1. Add up one period of spend: ads, salaries and commissions, tools, other.
2. Count the new customers won in that same period.
3. Enter average monthly revenue per customer and your gross margin.
4. Read CAC, payback months and the margin table — then decide whether to scale.

General information only — not medical, financial or legal advice. Figures cross-checked against public official sources (IRS / HMRC / NHS / WHO guidance); content last reviewed September 2026. For decisions that matter, confirm with a licensed professional in your country.

About this tool

Customer acquisition cost is the number that decides whether growth is a business or an expensive hobby. This calculator takes the honest numerator: not just ad spend, but salaries, commissions, agency retainers, software and everything else you spent to win customers in the period. Divided by new customers, that is a real blended CAC — not the flattering paid-only version. Then it goes a step further than most tools: using your average monthly revenue per customer and gross margin, it shows how many months of gross profit it takes to pay that customer back — the payback period CFOs actually ask about. Under 12 months is generally healthy; under 6 is strong. A comparison table shows payback at different margins so you can see what a pricing improvement would buy you. Everything computes locally in your browser.

FAQ

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